Molecular sieves are a commercially important class of crystalline materials. They have distinct crystal structures with ordered pore structures which are demonstrated by distinct X-ray diffraction patterns. The crystal structure defines cavities and pores which are characteristic of the different species. Molecular sieves such as zeolites have been used extensively in catalysis, adsorption, separation, and chromatography.
Molecular sieves identified by the International Zeolite Association as having the framework type MTW are known. Examples of MTW framework type materials include CZH-5, NU-13, Theta-3, TPZ-12, and ZSM-12. MTW framework type materials have a one-dimensional pore system with 12-membered rings.
U.K. Patent Application No. 2,079,735 discloses CZH-5 and its synthesis using choline as a structure directing agent.
U.S. Pat. No. 4,743,437 discloses NU-13 and its synthesis in the presence of a piperazine compound as a structure directing agent.
European Patent Application No. 162,719 discloses Theta-3 and its synthesis in the-presence of a quaternary nitrogen compound of formula BzNR3+X− where Bz is a benzyl radical, R is hydrocarbyl group and X− is an anion.
U.S. Pat. No. 4,557,919 discloses TPZ-12 and its synthesis in the presence of a pyrrolidine- or piperidine-containing diammonium compound as a structure directing agent.
ZSM-12 and its conventional preparation in the presence of a tetramethylammonium or tetraethylammonium structure directing agent are disclosed in U.S. Pat. No. 3,832,449.
U.S. Pat. No. 4,391,785 discloses a method for the synthesis of ZSM-12 from a reaction mixture comprising, as a structure directing agent, a compound selected from the group consisting of a dimethylpyridinium halide and a dimethylpyrrolidinium halide.
U.S. Pat. No. 4,452,769 and U.S. Pat. No. 4,537,758 disclose methods for synthesizing ZSM-12 from a reaction mixture containing methyltriethylammonium cations as the structure directing agent.
Other structure directing agents that have been used to synthesize ZSM-12 include DABCO-Cn-diquat cations where n=4, 5, 6 or 10 (see U.S. Pat. No. 4,482,531), bis(dimethylpiperidinium)trimethylene cations (see U.S. Pat. No. 4,539,193), benzyltriethylammonium cations (see U.S. Pat. No. 4,552,738), dibenzyldimethylammonium cations (see U.S. Pat. No. 4,636,373), dimethyldiethylammonium cations (see U.S. Pat. No. 4,552,739), benzyltrimethylammonium cations (see U.S. Pat. No. 4,585,637), bis(N-methylpyridyl)ethylinium cations (see U.S. Pat. No. 4,585,746), hexamethyleneimine (U.S. Pat. No. 5,021,141), decamethonium cations (see U.S. Pat. No. 5,192,521), bis(methylpyrrolidinium) diquat-n cations where n=4, 5 or 6 (see U.S. Pat. No. 5,137,705), and 1,6-bis(2,3-dimethylimidazolium)hexane dications (see U.S. Pat. No. 8,679,451).
According to the present disclosure, it has now been found that MTW framework type zeolites can be synthesized by interzeolite conversion (i.e., the transformation of one zeolite structure into another one) in the presence of polyethyleneimine, and, in some cases, it has been found that small crystal forms of MTW framework zeolites can be produced.